Explain Freundlich adsorption isotherm?

In 1909, Freundlich gave an empirical expression representing the isothermal variation of Adsorption of a quantity of gas adsorbed by unit mass of solid adsorbent with pressure. This equation is known as Freundlich Adsorption Isotherm or Freundlich Adsorption equation

x/m=kp^1/n

Where x is the mass of the gas adsorbed on mass m of the adsorbent at pressure p and k, n are constants whose values depend upon adsorbent and gas at particular temperature.

The plot betweplen the extent of adsorption

against the pressure of gas (P)at constant temperature (T) is called the adsorption isotherm.

Freundlich adsorption isotherm:

Freundlich adsorption isotherm gives an empirical relationship between the quantity of gas adsorbed by the unit mass of solid adsorbent and pressure at a specific temperature.

From the given plot it is clear that at pressureP_S,reaches the maximum valve.Psis called the saturation pressure. Three cases arise from the graph now.

Case I- At low pressure:

The plot is straight and sloping, indicating that the pressure in directly proportional toi.e.,

Case II- At high pressure:

When pressure exceeds the saturated pressure,becomes independent of P values.

Case III- At intermediate pressure:

At intermediate pressure,depends onPraised to the powers between 0 and 1. This relationship is known as the Freundlich adsorption isotherm.

On plotting the graph between logand logP, a straight line is obtained with the slope equal toand the intercept equal to log k.